The present invention relates generally to actuators in a heating, ventilating, or air conditioning (HVAC) system and more particularly to HVAC actuators that use brushless direct current (BLDC) motors.
HVAC actuators are used to operate a wide variety of HVAC components such as air dampers, fluid valves, air handling units, and other components that are typically used in HVAC systems. For example, an actuator may be coupled a damper in a HVAC system and may be used to drive the damper between an open position and a closed position. A HVAC actuator typically includes a motor and a drive device (e.g., a hub, a drive train, etc.) that is driven by the motor and coupled to the HVAC component.
Some HVAC actuators include mechanical end stops that define the ends of a range of movement of the drive device and/or the HVAC component. When the drive device is driven into the mechanical end stop, the drive device and connected components may experience an impulse force that can cause premature breakage. Existing solutions to this problem generally involve slowing down the speed of the motor as the HVAC component approaches the end stop. However, these solutions are unsatisfactory and do not sufficiently reduce the impulse force seen at the mechanical end stop.